Structure and cation distribution in perovskites with small cations at the A site: the case of ScCoO3

Wei Yi; Igor A Presniakov; Alexey V Sobolev; Yana S Glazkova; Yoshitaka Matsushita; Masahiko Tanaka; Kosuke Kosuda; Yoshihiro Tsujimoto; Kazunari Yamaura; Alexei A Belik

doi:10.1088/1468-6996/16/2/024801

Structure and cation distribution in perovskites with small cations at the A site: the case of ScCoO₃

Sci Technol Adv Mater. 2015 Mar 10;16(2):024801. doi: 10.1088/1468-6996/16/2/024801. eCollection 2015 Apr.

Authors

Wei Yi, Igor A Presniakov¹, Alexey V Sobolev¹, Yana S Glazkova¹, Yoshitaka Matsushita, Masahiko Tanaka², Kosuke Kosuda³, Yoshihiro Tsujimoto⁴, Kazunari Yamaura⁵, Alexei A Belik⁶

Affiliations

¹ Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 119992 Moscow, Russia.
² Synchrotron X-ray Station at SPring-8, NIMS, Kohto 1-1-1, Sayo-cho, Hyogo 679-5148, Japan.
³ Materials Analysis Station, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
⁴ Materials Processing Unit, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
⁵ Superconducting Properties Unit, NIMS, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
⁶ International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.

Abstract

We synthesize ScCoO₃ perovskite and its solid solutions, ScCo_1-x Fe _x O₃ and ScCo_1-x Cr _x O₃, under high pressure (6 GPa) and high temperature (1570 K) conditions. We find noticeable shifts from the stoichiometric compositions, expressed as (Sc_1-xM_x )MO₃ with x = 0.05-0.11 and M = Co, (Co, Fe) and (Co, Cr). The crystal structure of (Sc_0.95Co_0.05)CoO₃ is refined using synchrotron x-ray powder diffraction data: space group Pnma (No. 62), Z = 4 and lattice parameters a = 5.26766(1) Å, b = 7.14027(2) Å and c = 4.92231(1) Å. (Sc_0.95Co_0.05)CoO₃ crystallizes in the GdFeO₃-type structure similar to other members of the perovskite cobaltite family, ACoO₃ (A³⁺ = Y and Pr-Lu). There is evidence that (Sc_0.95Co_0.05)CoO₃ has non-magnetic low-spin Co³⁺ ions at the B site and paramagnetic high-spin Co³⁺ ions at the A site. In the iron-doped samples (Sc_1-xM_x )MO₃ with M = (Co, Fe), Fe³⁺ ions have a strong preference to occupy the A site of such perovskites at small doping levels.

Keywords: cobaltites; high-pressure; low-spin Co3+ ions; perovskites.